1. Technical Field
The invention relates to a tool for galvanically coating sliding bearings.
2. Related Art
The typical construction of a sliding bearing from the group of materials of the sliding bearings to be galvanically coated consists of a steel backing with a lead-containing or lead-free layer composite. The galvanic sliding layer applied to the running surface of the sliding bearing is a multifunctional material and performs various functions. Coating takes place in a box-shaped tool, which is also referred to as a receiver. In the coating, it is further to be ensured that the faces at which the bearing shells are divided (dividing face) are preferably not coated. Furthermore, a coating is not desired for the bearing backing, that is to say the cylindrical outer surface of the bearing shells. For that purpose, there are provided in the region of the bearing backing so-called thief cathodes or elements, which are suitably connected in such a manner that the bearing backing remains largely free of a coating.
Hitherto, one or more “towers” or columns of bearing shells have been erected one above the other in such a manner that the axial directions of the individual bearing shells coincide. The bearing shells are braced in this axial direction by means of a spring pressure. However, this structure is comparatively unstable, so that the columns of bearing shells frequently cave in, are highly coated on the dividing faces, and a considerable proportion of rejects is obtained. At the beginning and end of the column, so-called dummy shells of steel are used. The dummy shell at the beginning of the column of bearing shells to be coated covers the transition region between the air and the electrolyte. The lower dummy shell serves to stabilise the column and to maintain the tolerances of the deposited layer within the column of bearing shells. The above-mentioned thief cathode is fixed in the tool.